Slide-valve of steam-engines



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NV PETERS. PHDTO UTHOGRAPH UNITED sra'rEs TRT EEicE.

JAMES FREELAND AND ROBT. H. LECKY, 0F ALLEGHENY, PENNSYLVANIA. p

SLIDE-VALVE OF STEAM-ENGINES.

Specicaton of Letters Patent No. 22,794, dated February 1, 1859.

To all whom it 'may concern:

Be it known that we, JAMES FREELAND and ROBERT H. LECKY, of Allegheny city, in the county of Allegheny and State of Pennsylvania, have invented a new and Improved Contrivance or Mechanical Arrangement for Relieving the Slide-Valves of Steam-Engines from the Usual Pressure of the Steam; and we do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings and to the letters of reference marked thereon, similar letters referring to similar parts.

The nature of our invention consists in a mechanical arrangement or contrivance for avoiding the full pressure of the steam on the upper side and around the slide valves of steam engines, and for making the pressure on the upper and lower sides of the valve about equal, thereby obviating the usual severe friction of the valve and valvegear.

Figure l is a side view of our improved slide. valve. Fig. 2 is an end view of the same. Fig. 3 is a top view. Fig. 4 is a cut or sectional view.

To enable others skilled in the art to make and use our invention we will proceed to describe its construction and operation.

(A) is the valve seat, which is arranged and secured to the cylinder of the engine in the usual way.

(`B) is the sliding valve which has two supply openings (C), and one exhaust opening (E). The supply openings (C) and the exhaust opening (E) in the slide valve (B) correspond to the supply openings (D), and exhaust opening (F) in the valve seat' (A).

(K) is the cap of the slide valve (B) and is furnished with a steam chamber (G) which communicates through an opening (H) with the opening (D) in the valve seat (A) by means of the opening (C) in the slide valve (B).

(N) is the stufling box which holds the packing (I) around the steam pipe (L) by means of a thread of a screw on the stuliing box (N) and in the valve cap (K), the

`largest surface of the packing in all cases pressing against the steam pipe. The bevel or wed e shape given to the entering end of the stu ng box (N) and the beveled bottom of the packing chamber in the valve cap (K) will cause the packing (I) to press in against the steam pipe (L), thereby making a perfectly steam tight joint.

(M) is an armed flange secured to the steam pipe (L), and is used in connection with the four columns for the purpose of holding the cap (K), stuffing box (N) and steam pipe (L) in their proper posit-ion over the valve seat (A).

(O) are two studs screwed to the cap (K) and passing through the armed flange (M). Each of these studs is furnished with two nuts (P) one on each side of the flange (M). These studs are used for the purpose of preventing the cap (K) from swaging or twisting on the steam pipe (L), and also for keeping the cap (K) from pressing upward or from the valve seat (A) in case the pressure of steam in the cylinder, from a sudden reversing of the engine or any other cause, should be greater against the slide valve (B) than the pressure in the chamber (Gr) and the column of steam (J) in the steam pipe (L).

The operation of our improvement .is as follows; the valve (B) is operated by a cam or other suitable device. The opening (H) being in all cases smaller than the area of the steam pipe (L) the steam will press against the bottom of the chamber (G) and react against the end of the steam pipe (L) and column of steam (J), thereby holding the cap (K) down to the valve (B), by means of which the whole pressure of the column of steam (J) ,is prevented from pressing down upon and around the slidevalve (B) as is the case in the old style of constructing steam chests and slide valves; the steam in the cylinder pressing against theunder surface of the valve (B) will be about equal to the pressure on the upper surface of the valve through the opening (H), thus making the pressure about equal on each side of the valve, thereby avoiding a great amount of friction, and making the valve truly a balance and antifrict-ion valve.

Having thus described the nature, construction and operation of our improvement, what we claim as our invention and desire to secure by Letters Patent of the United States isfl. The arrangement of the armed flange M on the steam pipe (L), the columns (R), the studs (O) with nuts (P), and the cap (K), the Whole being arranged and secured (B), With the valve seat (A), the Whole beto the valve seat (A) as herein described ing arranged, combined and operated as and represented. herein described and for the purpose Set 2. The arrangement of chamber (G) with forth. 5 opening (H) as herein described and represented and for the purpose set forth.

3. The combination and arrangement of the armed flange (M on the steam pipe Vitnesses: (L columns (R), stu s (O) With nuts (P), DAVID Ri'roI-IIE,

JAMES FREELAND. BORT. H. LECKY.

10 stuing box (N), cap and slide Valve MARCUS W. ACI-IESON. 

